Isoprene → Isoprene butadiene

Participants

Reaction Steps

In a pressure-tight case equipped with a stirrer, 2700 g of cyclohexane, 70 g of a 40:60 monomer mixture of p-methylstyrene and styrene, and 2.52 ml of 1.3 mol cyclohexane solution of sec-butyllithium were placed and polymerized at 50° C. for 120 minutes. The resulting mixture was further polymerized with 326.6 g of a 60:40 monomer mixture of isoprene and butadiene for 120 minutes, and was further polymerized with 70 g of a 40:60 monomer mixture of p-methylstyrene and styrene for 120 minutes. The polymerization was then terminated by the addition of methanol and thereby yielded a poly(p-methylstyrene/styrene)-poly(isoprene/butadiene)-poly(p-methylstyrene/styrene) triblock copolymer. The triblock copolymer was dissolved in cyclohexane, and the resulting solution was placed in a pressure-tight case, whose atmosphere had been sufficiently replaced with nitrogen gas. The solution was subjected to hydrogenation using a Ni/Al Ziegler hydrogenation catalysis at 80° C. in an atmosphere of hydrogen gas for 5 hours and thereby yielded a poly(p-methylstyrene/styrene)-hydrogenated poly(isoprene/butadiene)-poly(p-methylstyrene/styrene) triblock copolymer [Mn=200000; proportions of polymer blocks=15/70/15 (by weight); hydrogenation ratio of poly(isoprene/butadiene) block=99% by mole] [addition block copolymer (I0-5a)].

Provenance & Evidence